Manufacture of galvanized iron



(No Model.)

W. B. SPEAR. MANUFAUTURE OF GALVANIZ-ED IRON.

No. 244,153. Patented July 12,1881.

t; Lg l A ATTORNEYX N, Pneus. mremlwwphf. wasmngm. u. c.

UNITED STATES PATENT OFFICE.

WIOKHAM B. SPEAR, OF PHILADELPHIA, PENNSYLVANIA.

MANUFACTURE OF GALVANIZED IRON.

SPECIFICATION forming part of Letters Patent No. 244,153, dated July 12,1881.

Application filed May 10, 1880. (No model,)

To all whom it may concern:

Beit known that I, WioKHAu B. SPEAR, of`

the city and county of Philadelphia, in the State of Pennsylvania, haveinvented certain new and useful Improvements in the Manufacture ofGalvanized Iron, of which improve,- ments the following is aspecification.

The objects of my invention are to economize time, labor, and materialin the manufacture of galvanized iron, and to produce a better and morehighly finished product; to which ends my improvements consist in anovel apparatus, as hereinafter fully set forth.

To enable others skilled in the art to practice my invention, I describethe same with reference to the accompanying drawings, in which- Figure 1is a vertical longitudinal central section through an apparatus forgalvanizing iron in accordance with my invention, and Figs. 2 and 3 are,respectively', vertical longitudinal vertical and transverse sections,each on an enlarged scale, through the zinc-tank.

A necessary preliminary to the practice of my invention, as to that ofall other galvanizing processes with which in my experience as a.manufacturer I have become familiar, is the removal of the scale oroxide from the sheets to be treated, which removal is ordinarilyeffected by immersion in a bath of sulphuric acid and water. As analternative and preferable method of pickling the sheets, they may beplaced in a tank containing a solution of sulphate of soda or potash,oil of vitriol, or commercial sulphuric acid and water, as I have foundthe surface of the iron to be in better condition after being cleaned bythe use of such mixture than if a simple solution of sulphuric acid hadbeen employed. After the sheets have been pickled they are removed fromthe bath and placed in a tank of water, from which they are removed, oneat a time, and examined, and any particles of scale that may remain areremoved by the use of a triangular scraper. Assumng either of the abovemethods to have been adopted, I take the sheets of iron which have beenpickled in the vat A and immerse them in a tank or vat, B, oflime-water, for the purpose of neutralizing the action of the acid uponthe iron, and preventing the corrosion or pitting of the latter thereby.In cases where the scale has been removed from the sheets by processesother than those involving the use of acid, as by abrasion or analogousmeans, the subsequent treatment with lime-water will be unnecessary, andis therefore dispensed with. I next pass the sheets to a tank, G,containing water, within which are placed a series of revolving brushes,C', preferably formed of rubber sections divided radially, so as topresent toothed or serrated peripheries, between which brushes the sheettraverses below the surface of the water in the tank, the rubbing actionof the brushes being exerted upon each side of the sheet, with theeffect of removing therefrom any accumulated deposit which may havesettled thereon in the rolling of the sheet, or in its immersion in theacid and lime-water baths, and providing a clean and perfect surface forthe deposition of the zinc. The sur plus water is removed from thesheets` by passing them between gum rolls C2 at'the outlet or deliveryend of the tank. The sheets are next passed from the rolls C2 to a tank,D, and traversed, between carrying-rolls d therein, through a bath of astrong solution of chloride of zinc of, say, 300 to 360 specificgravity, the purpose of which is to prepare their surfaces for thereception of the zine coating. A bath of dilute muriatic acid may, ifpreferred, be used in the tank D, in lieu of the solution of chloride ofzinc. After passing through the tank D the surplus solution is removedfrom the sheets by passing them between gum rolls d', from which theypass to a drying-oven, E, which is composed of sheet-iron, and, bypreference, heated by steam-pipes c, the sheets being traversed throughthe oven between iron carrying-rolls E. The steam for heating the oven Emay with advantage be superheated by means of a furnace, E2, or byappliances connected with the boiler in which it is generated. Thesheets are discharged from the drying-oven E, through rolls E3,into atank or vat, F, filled with zinc, which is maintained in a moltencondition by the application of heat around the tank, the sheetsentering the tank in a vertical direction, into which they are deflectedby the feed and guide rolls f, and passing into the molten zinc througha stratum'of chloride of zinc derived from a body of sal-ammoniac, whichcovers and floats upon the sur- IOO face of the molten zinc, upon oneside of a division-plate, f, extending across the vat F. The insertionand removal of the sheets vertically on opposite sides of thedivision-plate prevents the sal-ammoniac or resultant chlo ride of zincfrom coming to the surface of the bath with the iron and staining thesurfaces of the sheets, as is otherwise frequently the case. The use ofsal-ammoniac or chloride of zinc in the tank Fis not an essential 5 butI have found in practice its employment to be advantageous, andtherefore recommend it.' From the rolls fthe sheets pass under thesurface ofthe molten metal, being directed in their passage through thesame by curved guides f2, and are discharged from the tank in a finishedcondition by the delivery-rollsf3.

By the employment of the feeding and delivery rolls and the curvedguides the sheets may be passed, one by one, from the dryingovendirectly to and through the Zinc-tank, as rapidly as is consistent withthe proper deposition of the zinc coating upon their surfaces.

The labor required for handling the sheets in the manner heretoforeusually practiced is economized, and the delivery of the sheets from thezinc-bath between the rolls insures better finish and greater uniformityof coating than are obtainable when th e sheets are inserted and removedby hooks or tongs, as is ordinarily the case.

The relative arrangement of the several vats or tanks and thcdrying-oven in one connected series is such that the several operationsset forth can be consecutively and continuously performed, and the speedof the dierent pairs of rolls, between which the sheets pass in theirtraverse through the apparatus, should be substantially uniform, so thatthere may be no tendency to an undue accumulation of the sheets in oneportion of the apparatus or delay thereof` in another.

I claim as my invention and desire to secure by Letters Patentl. In anapparatus for galvanizin g sheet-iron, a water-tank provided withaseries of brushes arranged to rotate therein below thewaterlevel,combined with an adjoining tank having a series ofcarrier-rollers rotating below the level of the liquid thereincontained, and a pair of intermediate gum rollers located between thetwo tanks, or at the outlet or delivery end of the tank first named,substantially as set forth.

-2. The combination, in an apparatus for galv`vanizin g sheet-iron, of awater-tank provided with -a series of brushes arranged to rotate thereinbelow the water-level, a tank to receive a solution of chloride of zinc,and having a series of carrier-rolls adapted to rotate below the levelof such solution, a dryingoven having internal carrier-rolls, and a tankfor containing molten zinc, said tank being provided with guidefeed-rolls and a curved guide for governing the direction of sheets o t'iron in passing through it, substantially as set forth.

WICKHAM B. SPEAR. Witnesses:

J. SNowDEN BELL, WM. H. MYERS.

